OpenWrt support for Linksys MX4200

[O-S-T]

MX4200 V1

using build: https://github.com/testuser7/openwrt/releases/tag/qualcommax-d0cb3e3

DISTRIB_ID='OpenWrt'
DISTRIB_RELEASE='SNAPSHOT'
DISTRIB_REVISION='r0-d0cb3e3'
DISTRIB_TARGET='qualcommax/ipq807x'
DISTRIB_ARCH='aarch64_cortex-a53'
DISTRIB_DESCRIPTION='OpenWrt SNAPSHOT r0-d0cb3e3'

Fixed my previous 5GHz issue,initial impression is that it appears to be working very well. I will test further and report back if any issues.

phy0-ap0  ESSID: "OpenWrt5g"
          Access Point: D8:############
          Mode: Master  Channel: 48 (5.240 GHz)  HT Mode: HE80
          Center Channel 1: 42 2: unknown
          Tx-Power: 17 dBm  Link Quality: 60/70
          Signal: -50 dBm  Noise: -110 dBm
          Bit Rate: 1200.9 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ac/ax/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy0

phy1-ap0  ESSID: "OpenWrt2.4G"
          Access Point: D8:############
          Mode: Master  Channel: 1 (2.412 GHz)  HT Mode: HE20
          Center Channel 1: 1 2: unknown
          Tx-Power: 16 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -104 dBm
          Bit Rate: unknown
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ax/b/g/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy1

[SpectreDev]

Has anyone been able to get vlan working it seems to kill wifi when i try it

[lytr]

Does anyone have v2 but not from Community Fiber?

[judahrand]

It looks like your 2.4GHz radio isn't working with that build though? Which is an issue I'm also having atm. Both 5GHz radio are up and connected but 2.4GHz isn't happy.

phy0-ap0  ESSID: "XXX"
          Access Point: 00:69:1A:xx:xx:xx
          Mode: Master  Channel: 60 (5.300 GHz)  HT Mode: HE80
          Center Channel 1: 58 2: unknown
          Tx-Power: 19 dBm  Link Quality: 50/70
          Signal: -60 dBm  Noise: -107 dBm
          Bit Rate: 6.0 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ac/ax/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy0

phy1-ap0  ESSID: "XXX"
          Access Point: 00:69:1A:xx:xx:xx
          Mode: Master  Channel: 1 (2.412 GHz)  HT Mode: HE20
          Center Channel 1: 1 2: unknown
          Tx-Power: 20 dBm  Link Quality: unknown/70
          Signal: unknown  Noise: -103 dBm
          Bit Rate: unknown
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ax/b/g/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy1

phy2-ap0  ESSID: "XXX"
          Access Point: 00:69:1A:xx:xx:xx
          Mode: Master  Channel: 108 (5.540 GHz)  HT Mode: HE80
          Center Channel 1: 106 2: unknown
          Tx-Power: 27 dBm  Link Quality: 38/70
          Signal: -72 dBm  Noise: -109 dBm
          Bit Rate: 488.5 MBit/s
          Encryption: WPA2 PSK (CCMP)
          Type: nl80211  HW Mode(s): 802.11ac/ax/n
          Hardware: embedded [Qualcomm Atheros IPQ8074]
          TX power offset: none
          Frequency offset: none
          Supports VAPs: yes  PHY name: phy2

Edit: My 2.4GHz now does seem to be working! Just needed to force some devices to reconnect.

[lytr]

What is the problem with 2.4GHz radio? Is the SSID broadcast?

[judahrand]

There wasn't anything wrong with 2.4GHz in the end

However, my radio2 keeps choosing channel 128 when set to auto and in this state nothing will connect to it. Not sure what the issue is there but it works if I force it to channel 108.

[mgupta80]

@innovara

Beware that CF's firmware won't let you flash stock or OpenWrt, you'll have to repeat the process you followed in the first place to be able to flash OpenWrt.

Hi @innovara, Is there a reason why I should not use the version 2.0.6.211172 ?
https://downloads.linksys.com/support/assets/firmware/FW_MX4200_2.0.6.211172_prod.img

[innovara]

No, but I haven't tested it so I preferred to give you the exact steps that worked for me. I never used 2.0.6 firmwares because they have a NAT loopback bug and mapping ports 80 and 443 to an internal device kills your access to the router from the LAN as it directs you to this other internal device. Why the router would do NAT loopback on a connection coming from the LAN is something that only Linksys engineers could explain.

[innovara]

I haven't tried a VLAN as such but I have set up an isolated guest wireless LAN if that is what you are after. You could also remove one of the wired ports from br-lan and add it to the guest network.

[HOW-TO] Guest SSID on a separate LAN and firewall zone

I've recently set up my guest wireless network on a separate LAN and firewall zone to isolate it from my home network. I thought I would document it here in case it helps someone else. I am sure that you can find this information in other places. I used LuCI and a text editor while setting it up but, for simplicity, I am going to list the changes, and just the changes, to the text files involved. /etc/config/network config device option name 'br-guest' option type 'bridge' …

[mgupta80]

I managed to brick my MX4200v2, I think i missed 1 step and it's not booting up into openwrt

Could someone help me how can I unbrick it ?

[innovara]

You can manually switch to boot the other partition. Turn on the router, when the light goes on count 10, then switch off and wait for the led to go off. Do that 2 more times. That will tell the router that it has been unable to boot 3 times and switch to the other partition.
It's basically this: https://www.linksys.com/support-article?articleNum=316324

[Digitiain]

I did the same as @mgupta80 and tried this. I'm sure it worked, in terms of switching the partition (since the SSIDs I'd set up on OpenWRT disappeared), but the default SSID didn't start broadcasting. Any thoughts?

I was wondering if it's possible to re-flash using TFTP, but guidance seems to suggest you need to know the TFTP client or server IP, so not sure if this is practicable.

EDIT: flashing over TFTP worked nice and easily, it would seem. Easier to start from scratch!

[mgupta80]

Hi @Digitiain, I could not get it working using the power method for swapping partitions, is there a TFTP guide you followed?

[Digitiain]

This was bad info so removing (thanks @lytr). Best bet is using failsafe mode, turns out. There are no LED indicators (at least there weren't for me), so you have to just spam the reset button when you turn it on - I did it for about 10 seconds - and then try SSHing in again.

[lytr]

This description sounds... unbelievable

The router probably switched to the second partition after 3 failed boot attempts.

If the router does not boot from any partition, it will probably be necessary to disassemble and connect the serial console: OpenWrt support for Linksys MX4200 - #245 by lytr
It is worth adding the ability to run from USB to avoid such situations: OpenWrt support for Linksys MX4200 - #256 by lytr
Correct image names are:

• v1 - fw_setenv usbimage 'openwrt-qualcommax-ipq807x-linksys_mx4200v1-initramfs-uImage.itb'
• v2 - fw_setenv usbimage 'openwrt-qualcommax-ipq807x-linksys_mx4200v2-initramfs-uImage.itb'

[Digitiain]

For me, it did indeed switch after 3 failed boot attempts, but the original SSID didn't then start broadcasting, as I say. As such, I was unable to access the control panel to flash the new firmware, and of course the manufacturer disables SSH so that wasn't an option either. Hence resorting to TFTP.

I really didn't want to start disassembling anything!!

Agreed on the USB suggestions - I didn't realise you could do that.

[Digitiain]

Hmm. I now can't reproduce what I did before, @lytr . Perhaps it was somehow a fluke, but I don't know how I regained access to the device otherwise... I tried entering failsafe mode, but thought it had failed - perhaps it didn't and I actually got access that way, accidentally? I'll try a few things and report back.

[Digitiain]

Turns out failsafe mode worked. I'll get rid of my nonsense post from before!

[mgupta80]

Hi @lytr @Digitiain, It turns out the failsafe mode does not works for me. I have opened the router but it does not have pins. I have attached the photo of the cable that I currently have for serial access, do I need a different cable for this router?

[lytr]

You need a 3.3V TTL converter.